In short, is there? I'm playing a Master Summoner, and I'd love to get a Rod of Extend for use on my Summon Monster SLAs, but it obviously doesn't work. Is there any monster feats or anything that I've missed in my rulebook scouring that might allow me to obtain a rod or some such to extend spell-likes? Even old 3.5 stuff had empower, maximize, and quicken spell-like feats, but no extend.
To answer my own question, Frog God Games has the appropriate feat, which I imagine could be used to craft the hypothetical rod in question.
There are SLA feats such as quicken in the bestiary feat section, but those are the only ones that exist officially.
Thank the gods for 3pp, eh? :)