Tell ya what I'd also love to see right now, a low cost good quality wide prime - something in the 12-15 range, perhaps a second in the mid 20's, specifically for APS-C with a low f of about 1.8-2.0 to pair up with my current 15-85mm for low light wide use, pancakes perhaps ? What else ? How about a APS-C specific (L quality) 50-150mm f2.8 with IS ? to give crop bodies a decent 70-200mm alternative ? With an APS-C specific teleconverter - I don't want a big fat heavy lens and body hanging around my neck !
i think you've just quoted my wish list right there too. there was a patent app on this site i saw for an EFS 11 f/2, that would be perfect. A canon answer to the sigma 30 1.4 DC (ie, sharper wide open, i'd pay more for it, just smaller and cheaper than the 1.4L). And the protrait zoom, ~ 40-160 f/2.8 would be my range (to couple the 16-35), even make it FF and L, perfect for all-round wedding lens.
I've just had a look through a few of my favourite portrait shots of the past few months, - with the missus on a ferris-wheel with the niftyfifty head only,
- in a park with 15-85 at 55mm full body and a tree, 70mm waist-up from a lot closer,
- with friends in a park with the 70-300L at 124mm full body, 300mm head and shoulders, 200mm waist-up, i even let him touch my camera to take some shots of me (not as good) 70mm full body with a lot of extra space coz he held it horizontal.
(but ok, i don't do portraits (or anything else) professionally, these were opportunistic with the lenses i was carrying at the time.)
So yeah, they're all really over the shop, it really depends on how much space you've got.
the only advice i'd think of is that you can always crop an 85mm shot down, if you get the 100mm or 135mm, there's only so far you can walk back before you hit a wall. unless you're going to print them as 3'x4' posters, you don't have to fill the frame to use every pixel you can...