I may be completely biased on this (as we all are) but...
IMHO for high altitude performance in a single there is only one manufacturer that is worth considering and that is Mooney.
The factory installed TKS deicing system is FIKI certified (unlike any other single) and is extremely effective. This is a single engined piston aircraft that you can cross frontal systems with.
In the Ovation 2 (non-turbocharged) you can make FL200 at MTOW.
This will get you over most of the weather except the really convective stuff.
The Acclaim will give you FL250 which will get you over slightly more weather but with a far higher fuel burn.
These airframes are not only sleek and very aerodynamically evolved but also very rugged, time proven and superbly efficient, more so than anything else out there.
I've had a TKS equiped ovation 2 for almost 5 years and have no regrets.
The only thing I wish for is weather radar, IMHO the stormscope on its own is inadequate for flying through lumpy bumpy weather with.
I have no financial interest in the Mooney Airplane Company and this is based on my opinions of having flown (been flown in and trained in) lots of other stuff over the previous 10 years.
SB