I have the Techno heavy duty t-slot extrusions on my router. Good stuff, but expensive.
check this guy out on ebay selling full t-slot box table. No joining of smaller extrusions. 20 wide by 59 long. Four inches tall so bending stiffness is probably very good and would make for a rigid and more professional looking router. Price is very reasonable. I don't know or work for them.
http://cgi.ebay.com/ALUMINUM-T-SLOT-...2em118Q2el1247