I thought of waiting for the suggestion thread to open, but I'm not sure if what I'm proposing would be balanced at all, and maybe you guys have a better idea. I've been playing with the concept of a Shadowmage Shadowdancer, it's mentioned on the wiki that some people don't think it's a viable class combination. I don't think it's terrible, you can skill dump, you get Uncanny Dodge and Evasion, and you get caster levels. Rogue also gives all that, and it's a better skill dump, but no caster levels. Ranger will give you the extra feat you lose and provide a skill dump, but no caster levels. Higher caster levels are good, but should that be the only benefit for a Shadowmage dipping into Shadowdancer?
I think that much like how Ranger, Monk, and Barbarian classes scale with Shaman levels, something similar can be done with Shadowdancer and Shadowmage. Every 3 levels of Wizard counts as 1 level of Shadowdancer, gaining access to all feats and progression with the exception of Defensive Roll, Slippery Mind, Improved Evasion, and Hide in Plain Sight. So their Hide bonus scales, Shadow Daze scales, Shadow Evade and it scales, and they get Shadow Displacement.
I also thought that since the summoned shadow copies Str, Dex, and Con, but generally wizards/sorcerers are lacking in these areas, even with this shadow being summoned at a higher level, it's little more than a fallback plan. I think it would be neat to instead make the shadows summoned by Shadowmages into mini casters. Give them 1 or 2 low-level spells on a timer, spells based on Greater Spell Focuses invested in, then give them cantrips associated with those schools to spam while waiting for the cooldown. Maybe it can only cast spells from the Necromancy, Enchantment, and Illusion schools, and it copies the caster's main casting ability modifier for determining DC. Maybe the shadows copy metamagic feats, maybe that's too much. Basically the idea is to turn the shadow summon into something more like the Simulacrum spell, you could even have the summon upgraded through Epic Spell Focus Illusion as though it were the Epic Shadowlord feat.