I have the Hobby Topgun 46" span foam L-39 and love it! It flies very well on a Freewing 90mm fan and Freewing 1750kv motor with 6S 5000mah battery. 5 minute flights are common and flying on and off grass is also the norm. Cruises easily on less than 1/2 throttle and about 90mph flat out. Mine weighs 3.2kg with battery and is equipped with air retracts, HTG landing gear struts with alloy wheels, flaps, rudder and wheel brakes (only needed on pavement). The large 2 place cockpit is the centerpiece of the model and was scratch built by my father. Hobbyking has a great deal on them now without servos.
http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=15326
All my servos are the HXT-900 type and work well on this and my other 90mm models. At less than $3 a piece they are a bargain servo that haven't let me down yet (with hundreds of flights total in all my models).
Cheers Eric
(The pictures are from before I upgraded the nose gear strut and alloy wheels)