The A36 also ticks this box, and has undercarriage design that can cope with some non-tarmac operations. The 33/35 type has the potential limitation of CG moving to the aft limit with fuel burn, which I understand is less of a constraint in the 36.
A -550 Cessna 185 will win the useful load, range, non tarmac versatility stakes and still deliver a 150 KTAS cruise.
At what fuel flow will the C185 do 150KTAS?
Thread drift – why is it “KTAS” and in a flight plan we denote knots as N and kilometers as K? :-)
15/16 USGPH, an added benefit might be the ability to use skis and floats. Never thought of the KTAS convention but it precedes Eurocontrol flight planning codes. :)
RobertL18C wrote:
15/16 USGPH, an added benefit might be the ability to use skis and floats
That GPH is twice of a Mooney on similar KTAS (but can’t have it on floats/gass)
It is not KTAS that goes in FPL it is NIAS 
tmo wrote:
Thread drift – why is it “KTAS” and in a flight plan we denote knots as N and kilometers as K? :-)
Probably because the abbreviations have different origins. The use of “N” for knots in flight plans is of course because the “k” in “knots” is silent so it is pronounced as “nots”.
It is not KTAS that goes in FPL it is NIAS
It is definitely TAS
airways wrote:
It is definitely TAS
Thanks I always wrongly thought it was IAS (otherwise why CAT can still use Mach numbers? but probably the assumption is CAT & GA don’t mix ), a last one when ATC says fly 240kts (never ask me that yet), I guess they are referring to IAS?
I thought it is N for nautical miles per hour :)
faa.gov
ENTER the True Air Speed for the first or the whole cruising portion of the flight, in terms of:
Kilometers per hour, expressed as K followed by 4 figures (for example, K0830), or
Knots, expressed as N followed by 4 figures (for example, N0485), or
True Mach number, when so prescribed by the appropriate ATS authority, to the nearest hundredth of unit Mach, expressed as M followed by 3 figures (for example, M082).
when ATC says fly 240kts (never ask me that yet), I guess they are referring to IAS?
Correct. TAS for planning, IAS for sequencing.
Ibra wrote:
otherwise why CAT can still use Mach numbers?
Probably because they’re often Mach number limited.
