Yes they did (and still do) make a Tundra V6 Access Cab (2wd only). Not sure how common they are though.

The back seat should be larger than the T100, but whether it is big enough, you will have to judge for yourself.

I didn't think it was big enough when my oldest boys were outgrowing my non-T Toyota pickup (that and I didn't *need* a fullsize truck...).

hupptoy

99 4Runner SR5 3.4 Auto 4x4, 32" LTX A/T, 154K
93 Toy x-cab 22RE 5-spd 4x4, 31" LTX A/T, 150K