RentMeAHandbag.com seems to be the only site that offer women's shoe rentals. However, instead of a queue system, they offer weekly or monthly rentals. From the page I checked out, they're quite pricey ($279/week or $558/month for Manolo Blahnik pumps).

ShoeDazzle.com ($60M in funding) offers more of the type of service you described. However, instead of rentals, members pay $40 a month to receive a new pair of shoes selected by a Hollywood stylist.

It's also worth noting that in a 2011 interview, RentTheRunway.com ($30M in funding) said their future plans may include "product lines like shoes" - http://online.wsj.com/article/SB1000142405274870337340457614...