From what I remember (and few sources can help to confirm, since, during the pre-patch of TBC the max gold a single character level 60 could carry on a realm transfer was 5.000G (up from 2.000G) and the level 70 character was 10.000G.
If the numbers back from Patch 2.4.3 will be used then it should look like the following:
Not sure where your sources are? There has never been a gold cap between expansions. The hard gold cap in Vanilla was 214,748 gold 36 silver 47 copper because that was the maximum 32 bit value that could be handled by the game client… so that is the theoretical maximum per character that could come with you to TBC.