I just thought I'd pass this along to anyone who might be in need. I recently bought a Tisas 1911 that I thought was a little slippery for my tastes. I put some Hogue chain-link grips on it and a faux front strap checkering. This fixed my dislikes but while shopping I also found an unbelievable deal on a flat checkered mainspring housing. I just thought I'd pass it along if anyone was in need. The thing is all steel and only $19.99 shipped and comes 100% assembled with spring, plunger, stop and catch pin. It fits well and looks pretty good too. The one that came on the Tisas was grooved and worked well enough but this one definitely grips more.
Here it is if anybody needs one, (FIXED) 1911 checkered main spring housing.