No.
Generally, English-language versions are based on Japanese versions, but come out several months after the Japanese version does.
Current status
The English-language V5 came out in Jan/Feb 2008.
The Japanese equivalent of the V5.5 came out today (March 29) in Japan.
Bandai has said the English-language V5.5 will come out sometime this summer (July maybe.)
Future?
Looking back, at Japanse version release dates, you can see a pattern of two releases per year.
2004/ 3/20 Plus (similar to Connection V1 & V2)
2004/11/23 KeiTama (roughly similar to Connection V3)
2005/ 7/23 KeiTama Akai-series
2005/11/23 EnTama (similar to Connection V4)
2006/ 7/22 UraTama (similar to Connection V4.5)
2006/11/23 Suku
2007/ 2/24 Suku2
2007/11/23 FamiTama (equivalent to Connection V5)
2008/ 3/29 RoyalFamiTama (equivalent to Connection V5.5)
If this pattern continues, we might see a new Japanese version being released on 2008/11/23, and the English-language equivalent of it Jan/Feb 2009.