the Heroes of Cybertron line is pretty close. that would be my suggestion.
Definitely this! Heroes of Cybertron look great, there G1. but they are only in robot form. Not vehicle.
I also found some other line of toys at the dollar store for $5.00 a piece, ironically. I got a pretty good Starscream that does transform, but his jet form is too small, so I just keep him in robot mode. In robot mode he is the size of Atlas of the Thunderbolts. But he looks good. Their Optimus, and Bumblebee looks pretty good, too, but unlike Starscream, they are more modern somewhat like the movie. Megatron is a tank Megatron, if you can tolerate that. I like the original P-38 Megatron too much to change.
I picked up two stiff, non-transformy figures that were attached, oddly enough, to t-shirts for my son. One Optimus and one Bumblebee, of course. They are about the size of giants and look great; also, they fit on a regular sized dial and I am working on dials/powers for them.
JCPenney, I think.
Yeah, that kit is phenomenal, but pricey. I might haveta wait.
Have you considered looking at the Robot Heroes toys? They're a bit Chibi but not bad and they're all styled after G1. I collected the entire set and there are a TON of different characters, including beast wars and Transformers Movie if you wanted to branch out of just G1.