It is indeed possible to do this. However - the following will be required:

• XBMC must use the MySQL database setup
• Amarok must use the same Mysql DB xbmc is using
• the xbmc user has SELECT rights to the amarokdb.
• On the amarokdb - we have to crate a new view
• You are using the same media repository on both sides, means both amarok and xbmc will read the mp3 tags out of the same files.

If these requirements are met - migrating the data over from Amarok to xbmc is possible.

Note - the following examples are working on Amarok 2.7.0 and xbmc 12 (Frodo).
Modifications to be done on the XBMC DB. Here MyMusic32.

# View showing the real data
CREATE ALGORITHM=UNDEFINED VIEW `XTAPCount` AS select `song`.`idSong` AS 
`Xid`,`song`.`strTitle` AS `XSTitle`,`album`.`strArtists` AS 
`XARTName`,`album`.`strAlbum` AS `XALBName`,`song`.`iTimesPlayed` AS 
`XPlaycount` from (`song` join `album`) where (`song`.`idAlbum` = 
`album`.`idAlbum`);

We will need an intermediate table to store the local and remote playcounts.

CREATE TABLE IF NOT EXISTS `XTAPCount_last` (
  `LXid` int(11) NOT NULL,
  `LXSTitle` varchar(512) NOT NULL,
  `LXARTName` varchar(512) NOT NULL,
  `LXALBName` varchar(512) NOT NULL,
  `LXPlaycount` int(11) NOT NULL,
  `LXpcdiff` int(11) NOT NULL,
  PRIMARY KEY (`LXid`),
  KEY `LXSTitle` (`LXSTitle`(333)),
  KEY `LXARTName` (`LXARTName`(333)),
  KEY `LXALBName` (`LXALBName`(333))
) ENGINE=MyISAM DEFAULT CHARSET=utf8 COMMENT='Table to keep the playcount differences.';

The next view will actually show the differences in playcounts.

# View to show the differences in playcounts.
CREATE OR REPLACE 
ALGORITHM = UNDEFINED
VIEW `XTAPCount_last_diff` AS 
SELECT Xid, XSTitle, XARTName, XALBName, XPlaycount, LXPlaycount, (
XPlaycount - LXPlaycount
) AS XDiff
FROM XTAPCount_last, XTAPCount
WHERE Xid = LXid
AND (
XPlaycount NOT LXPlaycount
);

Let's insert the data for the first time. We take the values as they are

insert INTO XTAPCount_last(LXid, LXSTitle, LXARTName, LXALBName, LXPlaycount )
 SELECT Xid,XSTitle,XARTName,XALBName,XPlaycount from XTAPCount;

Update the LXPlaycount (This is the initial run).

UPDATE XTAPCount_last SET LXpcdiff=LXPlaycount;

Let's prepare the same for the Amarok side.

# View showing the real data
CREATE ALGORITHM=UNDEFINED VIEW `ATAPCount` AS select distinct `tracks`.`id` 
AS `Aid`,`tracks`.`title` AS `ASTitle`,`artists`.`name` AS 
`AARTName`,`albums`.`name` AS `AALBName`,`statistics`.`playcount` AS 
`APlaycount` from (((`tracks` join `statistics`) join `artists`) join `albums`) 
where ((`tracks`.`id` = `statistics`.`id`) and (`artists`.`id` = 
`tracks`.`artist`) and (`tracks`.`album` = `albums`.`id`)) order by 
`statistics`.`playcount` desc;

Intermediate Table - where we will store local and remote (here) XBMC Playcount.

CREATE TABLE IF NOT EXISTS `ATAPCount_last` (
  `LAid` int(11) NOT NULL,
  `LASTitle` varchar(512) COLLATE utf8_bin NOT NULL COMMENT 'Song Title',
  `LAARTName` varchar(512) COLLATE utf8_bin NOT NULL COMMENT 'Artist name',
  `LAABName` varchar(512) COLLATE utf8_bin NOT NULL COMMENT 'Artist Name',
  `LAPlaycount` int(11) NOT NULL COMMENT 'Playcount',
  `LApcdiff` int(11) NOT NULL COMMENT 'Playcount difference to last time',
  PRIMARY KEY (`LAid`),
  KEY `LASTitle` (`LASTitle`(333)),
  KEY `LAARTName` (`LAARTName`(333)),
  KEY `LAABName` (`LAABName`(333))
) ENGINE=MyISAM DEFAULT CHARSET=utf8 COLLATE=utf8_bin COMMENT='Table containing last play state.';

LAst but not least, the View to show the differences in playcounts.

CREATE OR REPLACE 
ALGORITHM = UNDEFINED
VIEW `ATAPCount_last_diff` AS 
SELECT Aid, ASTitle, AARTName, AALBName, APlaycount, LAPlaycount, (
APlaycount - LAPlaycount
) AS ADiff
FROM ATAPCount_last, ATAPCount
WHERE Aid = LAid
AND (
APlaycount  LAPlaycount
);

Make the Initial data dump

INSERT INTO ATAPCount_last(LAid, LASTitle, LAARTName, LAABName, LAplaycount ) 
SELECT Aid,ASTitle,AARTName,AALBName,APlaycount from ATAPCount;

And put the playcount into the temporary Field LApcdiff (Amarok DB only here).

UPDATE ATAPCount_last SET LApcdiff=LAPlaycount;

Now comes the Sync Process. Depending on the number of lines you have in there, it may take some time. With 12K Songs - it takes around 12 Minutes for my DB's to sync.
Sync the Data Amarok -> XBMC

UPDATE MyMusic32.XTAPCount,ATAPCount_last_diff SET 
MyMusic32.XTAPCount.XPlaycount=(MyMusic32.XTAPCount.XPlaycount + 
ATAPCount_last_diff.ADiff) WHERE ASTitle=XSTitle AND AARTName=XARTName AND 
AALBName=XALBName and ADIff > 0;

Once this is done - set the current state with:

UPDATE ATAPCount_last,ATAPCount set LAPlaycount=Aplaycount WHERE LAid=Aid;

Put the playcount into the temporary Field LApcdiff (Amarok DB only here).

UPDATE ATAPCount_last SET LApcdiff=LAPlaycount;

Sync the Data XBMC -> Amarok

UPDATE amarokdb.ATAPCount, XATAPCount_last_diff SET 
amarokdb.ATAPCount.APlaycount=(amarokdb.ATAPCount.APlaycount + 
XATAPCount_last_diff.XDiff) WHERE ASTitle=XSTitle AND AARTName=XARTName AND 
AALBName=XALBName and XDiff > 0;

You're done.