I know that to most travelers a rental car is just a means of getting from one place to another, but I am not exactly like that. In fact, since I discovered that Sixt (and, subsequently, Europcar and Avis) have some fun stuff in their fleets, I've tried to build a Euro trip around being able to drive some fun stuff that I don't have back at home in the States. I know there are more folks than me out there, so I'm just curious to find out what your experience has been with renting cars that up the fun quotient some.

So far, I've been able to find out the following:

Europcar Selection

Type in "Selection" into the "Location" field and you can see a list of these premium locations. A fairly decent spread around Germany, plus, for some reason, London Excel are available.

Seems to be hit-and-miss with confirmation. I've had a couple of reservations confirmed right away, but for some reason today their search results changed to reflect "low availability", which basically meant you have to hear back from the branch about whether or not the car is actually there. Unfortunately, this is par for the course as their availability is not real-time. They do have some neat stuff (I'm not including London in this list, as they have quite a few more):

Fiat 500 Abarth - by far the cheapest (can be as low as 30 Euro/day). The only manual of the bunch.
VW Golf R
Jaguar F-Type S AWD

The Golf R and the Jag (surprisingly) are within about 25% of each other, price-wise. There are also AMG Mercedes and Audi A6, but they are a fair bit more. Non-airport locations are (obviously) cheaper and one-way rentals between Selection locations are permitted with what looks like a very reasonable surcharge (less than a day's worth of price). Corporate rates do work; 40509211 - La Carte Accor holders, publicly available - seems to have the best discounts. The downside is the 250 km/day restriction.

You have to click around the categories at the top as sometimes they don't make sense. The "Selection" category in particular seems to exclude some vehicles that you'd think should be in there, because, you know, the entire branch is a "Selection" branch. Also, the fleet guide on the main Europcar Website is nonexistent with respect to these vehicles.

Sixt Luxury

This is what started it all for me: when I saw that Sixt had the A45 AMG, I knew I had to try to get my hands on one. So far, it's proven to be rather challenging as I keep getting rejected even after being told by Sixt themselves to request the specific branches that should have the vehicles available. So, same old song - availability is not real-time and has to be confirmed. Sixt is generally pretty decent about communicating via e-mail, but you have to catch them during the times they're there and the hotline rarely has the answers as it's up to each individual branch to confirm availability. Really annoying that it has to be like this.

My three top standout categories are LTAN (Alfa Romeo 4C), CCAN (Merc A45 AMG) and SSXM (BMW M2/M240i). Unfortunately, in the latter you can't pick just the M2 - it's whichever of the two models the station has. No manuals, either. The S5 coupe/S6 Avant and the Mustang are also available for fairly reasonable prices (I've seen rates as low as $42/day in Munich). The M3 is a bit more expensive (no use listing the others, as they are considerably more).

Avis Select Series

The UK site seems to have a list of locations and a fleet guide. Unfortunately, the booking system seems to be restricted to European sites - the U.S. Avis.com page won't show these cars. Also requires branch confirmation. One-way not possible. AWDs don't seem to do anything to prices, either. The distance restriction seems to be less stringent than Europcar's (I think it calculates to 500 km/day per my last quote). Availability even for a quote is incredibly hit-and-miss. I've had occasions where I'd put in for six days and I'd get availability, but put in either five or seven (or even change an hour back or forth) and get nothing. Pretty-looking but horribly-working web interface.

The two most affordable vehicles in Germany are the VW GTI Clubsport and the VW Golf R and the Mustang, but both VWs are going away in mid-April, to be replaced by a regular GTI. Italy has the Abarth 500 and 124 and the Alfa 4C, among others.

So, that's about it. Would be curious to find out if any of the other big rental companies have similar offerings and if you've ever rented those vehicles before and how your experience was. I know Hertz has the Prestige collection, but I've never really seen performance compacts there - more Porsches and Range Rovers and the like.