WAAS is not the issue. SkyView already has WAAS in the SV-250 GPS module.
To use GPS for primary navigation in IFR during the approach phase, the AIM says:
and:
Note that there is no mention of WAAS. The real mention is the TSO. The equipment must have a TSO authorization, and the database must come from there.
SkyView has a WAAS GPS. We could put all the databases in the world in SkyView, but it still wouldn't be legal to use.
We have more info here:
http://dynonavionics.com/cgi-bin/yabb2/YaBB.pl?num=1362597418
If you are looking for ADS-B OUT, but not IFR navigation, the units Isaac mentioned are OK (except the Grand Rapids which doesn't have a TSO, and is the same as the Dynon GPS). If you want to navigate with the GPS and not just do ADS-B OUT, then only Garmin, Avidyne, and Bendix King sell new GA units that will do what you need.
If you only want enroute or non-precision (and don't care about ADS-B out), the other devices like a 300XL can work, but note that these are not ADS-B OUT compliant when 2020 comes around. ADS-B OUT needs a precision approach capable GPS (Generically, one with WAAS, but also fully certified)