I haven't seen any HQI retrofit. It's required the UV glass. Unless you DIY, I don't think there is any HQI that is not pendant. There is good pendant that you don't mind showing and there is ugly one that you want to hide inside the canopy..
If you are talking about a complete setup like the sunpod, which is a pendant to me, there are some other expensive brand. Look on RC. Alan (hyacinth) is selling the Giesemann fixture. Very nice unit but expensive. You can buy a PFO HQI pendant and PFO Electronic ballast or Icecap ballast. That would be nice too.. The Giesemann fixture is too expensive to me.