Actually, Vulpix has some merits for sun-setting (I don't mean making the sun set, I mean causing the weather condition) as well. 100 speed lets it run a scarf to revenge kill most unboosted pokemon, something Groudon can't boast. Even though its special attack is low at 77, Sun + Stab will certainly help in that department.
Let's take a look a sun as a whole, shall we? We may have Magby breaking down walls with its great mixed stats, Sun and STAB boosted Flare Blitz and Fire Blast, 104 speed, and considering the fact that most walls have become one sided through this process (I'd include calcs, but I'm unable to download the calculator). Bulbasaur is going to be a deadly sweeper, although Ivysaur may be chosen so you're not outsped by Abra under sun. Bellsprout is a slower, but a lot more powerful version of Bulbasaur. Victrebell could be used for speed, but you really aren't outspeeding anything beyond Spearow, Swellow, and Sneasel (who should be packing priority anyway).
Oh, and a quick fun fact. Tropius, through this process, only loses a single point in HP. Maractus has absolutely no change whatsoever.