HeatsinkUSA, 10" x 10" $30 + $5 handling + ~$11 shipping = $46
LEDs from SatisLED (they are FAST shippers) I would do one 3W 660nm LED for every 2x2 area (since it's single-sided) or as little as one for every 3x3, sio you're looking at somewhere between 16 and 32 of those, then 6:1 red:blue so 3 or 5 blue 450-455s, those are about $1.79 each from Satis = between $35-$70
Thermal pads or Arctic Silver adhesive = $7 to $20
Driver, $34
Wire, solder, plug for driver, $10
Total cost $130 - $180
figure in lamp change cost and energy savings and it's a no brainer