I can't speak to the Spuhr stuff, but it sure looks pretty.
Near's bases work perfectly, so purchase with confidence.
With respect to the bipod - I know the OP has already stated he is set on an aftermarket set up, but to all those that own or are looking at the TRG - the factory bipod is truly designed for the gun. It isn't an add-on or an afterthought like so many accessories. It's hinge point is set to that of the centre of barrel.
It's footprint is low and wide, with positive claw feet, parkerized finish and fully adjustable. It swivels out of the way either forward or rearward, and when tucked up, doesn't interfere with the operation of the rifle in positional shooting.
If there is only one accessory for the TRG that needs to be OEM it is the bipod.