Babka - I think Craig makes a very good point. I am in a similar boat. Here is my summary of what I have found:
a) At a diagonal of ~140" and below, there are several sub-$10k projectors including the Panny that can do the trick.
b) When you start edging towards 150" and above diagonal, the cost of the projector starts jumping exponentially if you dont want contrast or screen ft-lamberts to suffer. You rapidly come to the conclusion that to have the same contrast and brightness at a size of ~140-160" diagonal, that you are used to with a JVC or a Panny at sub 140" (diagonal), you have to get either a mid end DPI or projection design or something in that range - which is starting to touch $20k. If you want to go even larger to 186" diagonal as you mentioned, with o compromise on contrast or brightness at all, you pretty much are talking a Sim2 Lumis or a DPI Titan or projectiondesign aviello. and even a Sim2 Lumis will probably struggle at 186" diagonal although I think some on the forum do have a Sim2 driving a screen roughly that size.