Thanks to all of you for your input. Although I'm getting a 2011 X5 in the coming month, I have to consider retrofitting the DRL's with one of these retrofit alternatives. In trying to summarize:
H8 alternatives:
1.) H8 GP Thunder: Tried them on my current 2007 X5 - Useless !!!
2.) European 2011 X5 with Xenon lights, seem to be fitted with an H8 bulb for the DRL's. BMW part # 63 21 7 160 782. It's available on BMWpartsoutlet for $28.95/pc
http://www.bmwpartsoutlet.com/partlocator/index.cfm?action=searchCatalogOEM&siteid=215944
the question remaining: does it work?

LED alternatives:
1.) City Vision LED (from Modbargains) - 1 pc body/2 LED's:
http://www.1addicts.com/forums/showthread.php?=7934577
They do not seem to be very visible in day light and reported to fail by some users.

2.) GP Thunder Dual-LED H8 Ring Marker (30 deg. opening)-2 pc V-Shape body/2 LED's ($ 150)
http://www.hid-lights.com/products/led/led-bmw/2979W.htm OR
http://cgi.ebay.com/ebaymotors/Angel-Eyes-E92-E93-E70-E82-2-LED-H8-bulbs-Marker-BMW-_W0QQcmdZViewItemQQhashZitem3c9d36c862QQitemZ26033 5650914QQptZMotorsQ5fCarQ5fTruckQ5fPartsQ5fAccesso riesQQxZ22QQyZ4
http://www.hid-lights.com/products/led/led-bmw/2979W.htm

3.) iJDMtoy 60 Deg opening of the one above (Korean made)-2 pc V-Shape body/2 LED's ($ 120) - Apparently more efficient because of the wider angle but no user post that I have seen yet.
http://store.ijdmtoy.com/BMW-Angel-Eyes-High-Power-LED-H8-Ring-Bulbs-p/led_bmw_halo_s7.htm

4.) PIAA H-499 H-8 LED Marker - 2 pc V-Shape body/4 LED's ($ 285)
Similar to the above Korean design with 2 add'l LED's, closer to the base of the "bulb". No review that I have seen/read.
http://cgi.ebay.com/ebaymotors/PIAA-H-499-H-8-LED-Marker-Angel-Ring-BMW-Series-_W0QQcmdZViewItemQQhashZitem3a5cda8f53QQitemZ25066 5930579QQptZMotorsQ5fCarQ5fTruckQ5fPartsQ5fAccesso riesQQxZ38QQyZ9

5.) Faulkner BMW OEM LED ANGEL EYE UPGRADE - 2 pc T-Shape body/4 LED's ($ 225)
Similar approach to emitting the light closer to the ring openings, using a different shape. Total of 4 LED's per "bulb" with 2 at the base. No review that I have seen/read.
http://cgi.ebay.com/ebaymotors/BMW-OEM-LED-ANGEL-EYE-UPGRADE-REPLACES-H8-BULB-_W0QQcmdZViewItemQQhashZitem439ff0f332QQitemZ29044 6177074QQptZMotorsQ5fCarQ5fTruckQ5fPartsQ5fAccesso riesQQxZ35QQyZ4

6.) MDS LUX H8 Rings for BMW - One body "bulb". The v.2 seem to have 4 LED's ($ 249).
http://www.namotorsports.net/detail.cfm/part_cd/MDSLUXH8
There has been a very good post by Epacy, with plenty of pictures, even in day light.
http://www.xoutpost.com/bmw-sav-forums/x5-e70-forum/74822-lux-led-v2-installed-angel-eye-bliss.html
Downside is that some of the components seem to have to go outside of the headlight assembly (heat dissipation).

I'm interested to read some reports from the people who have bought either the PIAA H-499 H-8 LED Marker or the T-Shape Faulkner to see how these ones do.
Anyone?


HID alternatives:
They seem VERY bright and likely to generate a lot of heat ... Don't think they represent a true alternative in trying to get closer to the latest BMW OEM DRL's.