L1B switching within companies having joint venture..

[Asame]

My visa status is L1B (Blanket L1) through Company A. I started working on L1B since July 2004 & I went back to India in June 2005. I came back to US on same L1B in August 2006 (i.e. after gap of 1 year 1 month) and continued working till today. My extended I 94 is valid till April 2010. Till April 2010, I will be completing four and half years on L1B. Company A do not want to renew my L1B because it will give me extension of only 6 months i.e. till Oct 2010. (In short Company A do not want file any visa for me)

Company A has joint venture relationship with Company B. (Company B has around 8% shares in Company A)
I am on payrole of Company A however I do all the work for Company B (To simplify Company B is customer of Company A OR Company A is supplier for Company B). Company B do not want me to go away.

In order to continue my work with Company B, what is the best solution.
1) What are the options I (or Company B) have to continue my work in USA.
2) Can company B renew my L1B visa ?
3) Can company B convert my L1B visa to L1A visa ?
4) If Company B files H1B for me then probably I will get H1B for two and half years since Oct 2010. (Considering I will go back in April 2010). Then Is it possible for me to apply for GC and continue working without worrying for the 6 year H1B period ?

OR what is the best option for me and Company B to continue the work ?

Thanks.