The upper end of the non-Tamiya spectrum isn't a bad idea either, being as mentioned above the Taigen / Asiatam based metal hulls with torsion bars that you can order in pieces and assemble, but again as stated above these aren't true kits and are rather large separate components that just need basic assembly and painting.

Imex / Taigen is a domestic retailer, as is MatoMart and immortal hobbies.

Across the pond I'm VERY impressed with the offerings from Dom @ rctank.de, as well as welshdragon models. These tanks can easily get over $500-600 all in, aren't quite as high end as Tamiya but are definitely not toy grade. The last 2 years has seen a major increase in quality in what you can call HengLong BASED models. I have a Tiger I and KV-2, both done up with all metal drive parts, torsion bars, metal wheels with full ball bearing support, ball bearing gearboxes, recoil & excellent sound with the new TK-22 Clark boards. Tough as nails, excellent fighters. I enjoy them a lot!

Next on the list is the full metal hull Panther G with similar components.. so much armor!