Actually I asked it beacuse I'm attending an aircraft design course at university; the goal is to design an escort for the MV-22 so I was thinking about a turboprop light attack aircraft able to take off and land on a LHD wasp class ship.
Hmm...Well, if that's your objective, I'd suggest not going the fixed wing route. In my mind, using CTOL aircraft add some fairly significant restrictions and drawbacks.
Firstly, the length of the takeoff and landing rolls dictates and reduces the amount of deck you have available for other missions, aircraft, equipment, etc. This reduction in available deck space limits the number of helicopter/Ospreys you can launch, load, and recover at one time, which has obvious drawbacks.
Secondly, safety reasons may dictate that the deck must be completely cleared during Tucano operations. For example, let's say a Super Tucano pilot overshoots the deck and has to go around again. But if the forward part of the flight deck is being used for V-22s or heloes while you're doing recoveries, then the possibility of a very, very serious accident arises.
There was some discussion about this on the RAN thread a while back, if I recall correctly, so I'd recommend looking back at it. The discussion on it starts here about midway down the page and continues intermittently until page 220 (
http://www.defencetalk.com/forums/navy-maritime/royal-australian-navy-discussions-updates-5905-215/)
If a VTOL Osprey escort is you goal, I'd suggest simply modifying an existing tiltrotor design. It would have the speed to keep up with the V-22s, but its warload, range, etc. would exceed that of a helicopter. The idea isn't a new one, but it's worth revisiting. (
V-22 Escort).
Or you could go with a VTOL/STOVL jet design such as the Harrier, Yak-38, Yak-141 (Russian prototype of a VTOL jet), or the F-35B. This, is my mind, is the best option, since it also gives your force a degree of limited tactical air defence and interdiction capability.