The L.F. lamp is rated 800 lumens but it's not truly that strong... I'd have to estimate it at around 550 lumens and these drop-ins offer more of a flood pattern than long throw.
Yes, there is the Malkoff conversion but they are more expensive and do drastically change the look of the light setup. For the M951/M952/618FA/618FGA we modify the Malkoff M61's to drop right in ($43.50 delivered on an M61 or M61L) so no conversion bezel is needed. In the case of the Millennium 9v & 12v lights I'm not sure the MDM4 conversions that use the M61 or M91 lamps will satisfy all users but the M91T variant certainly provides a worthy price-to-performance ratio.
IF, you want to keep it all Surefire then there is always the KX9 Turbohead LED conversion but it will be over $200.