Depends a lot on which type of hybrid you're talking about.
Hybrids of the early 2000s generally fell between FWs and long irons in the distance they delivered. For these hybrids, the shafts were longer than long irons, but shorter than FWs. Also, hybrids tended to have a very high launch. Some people started replacing long irons with hybrids, with a 4H outdistancing a 3i.
Recently, some companies have been offering iron replacement hybrids. Mizuno is an example with its Fli-Hi DLR (direct long-iron replacement) varieties.
- MP Fli-Hi offers a 2H (no 2i), but also a 3H and 4H that match the MP series 3i and 4i exactly for loft and shaft length.
- JPX Fli-Hi offers a 2H (no 2i) plus 3, 4, and 5Hs that match the JPX 800 irons.
TaylorMade gets interesting with the RocketBallz line. For the straight-up (non-Tour) RBZ hybrids...
RBZ 3H = 19* / 41" .... RBZ 3-iron = 17.5* / 39.5"
+ 1.5" shaft length should trump 1.5* loft difference to give the 3H more distance....
TM touts the RBZ 3i, 4i, and 5i as having "metalwood-inspired" head construction. Are these clubs covert hybrids?