As cool as it would be, the spool time would keep it from being a real down and dirty bush plane.
You are entitled to your beliefs, but I can assure you (as a very current, and fairly savvy turbo prop guy) that anytime someone cites spool or lag issues of a turbo prop as a limitation, it is either;
A) because they read that on the internet... or
B) because they have only been instructed in traditional (pavement to pavement) turbo prop operation.
All you are asking out of a power plant and prop when you make power setting changes (in slow speed configurations) is for a
thrust change.
It just happens that in a typical small airplane power plant atmosphere, jabbing the throttle yields the fastest results.
With a turbo prop, if you really want to master the bottom end, (I'm talking short final and tighter) you need to forget about the fuel, and learn to manage the propellor. A good T-prop stick that can really play stol, moves the prop just like a good cub pilot moves the throttle. This will include up to and beyond beta, and even a whole lot of reverse.
Spool up? Lag? NONE! want proof? watch your average constant speed prop (recip powered) guy make a lap around the patch. What happens when he rolls on to final? The prop goes full fwd, and the airplane stand on its nose.... that fast!... Well... that's exactly how fast you turbine prop moves, but it's almost always more prop, and more power (thrust)!...
But wait... there's more... Pull a turbine in to a handful of reverse 20' off the ground and it's going to try and stop (literally), mid air, .... this sounds...well, not good... but the instant you nudge the power lever forward, it's going to see a shot of fuel and shot of prop, and it's literally going to leap... instantly...
This blows smoke in the face of any 'spool' or 'lag' theories. And so far, I am generically suggesting Pratt models (the inherently slowest of the bunch to spool up) In fact, I would go out on a limb and say that a good turbine stick in a turbo prop can yield quicker THRUST response, than a recip driver any day.
A non indoctrinated turbine driver? well... that'd be like asking the average Mooney / Cirrus / Bonanza guy to extract maximum performance out of a cub... or the space shuttle for that matter.
Side notes...
Fight idle vs ground... if you are a Pratt or similar power plant driver, forget about what you read anywhere and do what fits you best. there is no magic Mojo going on in either case. If you float in flight idle, it's because you haven't slowed down the wing. If you spool down too much in ground idle it's because you haven't learned how to keep the engine alive while slowed up. The difference between the two is tantamount to where you stoped moving the lever. Yes good rigging is a must if you want the best results.
In Garrets and similar use it appropriately or you will be in for quite a surprise. When the say FLIGHT idle, they mean it.
Flairing with the prop...
If your approach has you at the gate (beta). or a smidge behind (reverse, good btw!) at 1' agl, keep on pulling back on the prop. it will flair, set the tail down, and let you keep on rolling in to reverse. Do this in an airplane that weights 5-6,000 lbs
empty, and you will easily land and stop in C-180 distances... It is amazingly easier for me to land and taxi off in my overweight work plane than it is in my light weight C-180. Same airstrip, to same taxiway.... BTW, it will
NOT swap ends here any worse than on
take off... torque and P factor exist either way, if you can handle a take off, you can handle a hand full of reverse, just be ready to handle it!
Rough and tumble, river bottoms jeeping whatever....
If you truly believe turboprops are somehow not up to the backwoods environments, you have not been watching the trends (and not necessarily new) in commercial back country aircraft. Every genre is cycling out their aging recip fleet with turbo props...
Having said all that, and with my obviously strong bias towards turbo props, I have to say I strongly agree with Greg.
The concept is good, but currently I seriously doubt you could build a turbine cub that made sense financially, nor that most recip transplants could use any better than the do their trusty O-320/40/60's... probably not even as good.
Draco? that was a heavier bird, with a turbine fluent builder/pilot. It is probably in the weight class where a turbine currently just starts to shine. A Soloy 207 is an aging concept that was 90% of Draco decades ago.
Take care, Rob