I fly regularely at FL140 when operation conditions allow it or demand it, but that is still almost half of the altitude at wich you enter the RVSM flight levels so it is imposible to imagine a L410 equiped for it because there is no possibility that you would ever need it.
Also for your info I happen to know a guy who flew test flights on the secound prototype and he climbed it almost to FL250 but he said to me that is irreasonable to fly it above FL170 because performance is so poor and it can be done only with empty aircraft.
Never the less for operations it was intended to (read "mule" kind of job) it is almost perfect aircraft. the problem is that a lot of them fly with poor or no maintenance and MTOW is almost always below actual TOW.This makes bad comercial for this, if you ask me, beautiful bird.