diy t&g panels ?

T+G boards can be made in workshop but you need good equipment including a table saw, thicknesser and a router table with feather boards. I have made them as thin as 8mm but they need to be carefully routed under control. They will contract after a few months exposing small gaps so remember the 'tongue' will be exposed. If you don't have a router table its possible to make a 'loose tongue' with veneer coated 4mm ply by cutting on a table saw but that's a lot of work. 4mm ply is available with the usual American veneers including ash, teak and mahogany and is fine to use on its own as the back of a cabinet.

If it is going to be painted I'd go for a sheet of MDF and route 2/3mm grooves in it with a V bit. Mark out lines and run the router against a straight edge.

Its the back of a cabinet fellas - you don't want something that weighs a ton.:D
For quality work like a dresser I think T+G boards made from the same wood look better but if its just basic storage then any sheet panel up to about 8 mm would do ?