We, that is, I and my long-term colleague, who have been successfully developing sites together for quite some time (eg. the datacolor.com site), got something like this sitting around (actually its in its finalization stage, scheduled for its initial rollout at the end of this week).
But: Its not to be sold on some kind of market place platform, eg. Envato or so, but rather is planned for … hm … lets call it … individual / custom release / on-demand. There is going to be a simple site displaying its main features and a few RL sites as portfolio material. Depending on what my colleague is gonna suggest, its either going to feature some base-line example packaging prices, or a classic “ask for a quote” contact option.
Aside of that, I’ve built plugin bundles speciifically for longer-term clients, which have been reused in several of their projects, again and again (think of design agency which plans and designs sites for clients).
So, depending on the market and how you sell that, this can work out, but also can fail nastily. Its usually a thing of the classic “Vitamin C” (Contacts) or “Vitamin M” (Mouth-to-mouth propaganda).