so you asked for a mastering engineer and got some folks suggesting the absolute best in the world.............and they are expensive, and some other folks just joked it, sorry you didn't yet get much of any real world options...maybe I can help.
Check out my tunes here
http://scottfranson.com/Audio.html
I mixed and mastered all of them. If you like what you hear, send me a wav file and I will give it a shot. I'll send it back mastered but clipped off at the end, if you like the sound, I'm only $30 per hour and it usually takes about an hour per song....depending on your recordings.
Do not put anything on your master strip (except a meter) and get your peak about 1dB below digital zero, then bounce your tune to a 2 track, multiple mono 24/96 file, and please use the tweak head setting when you bounce.
Scott Franson
www.theranchrecordingstudio.com
Intel Q9650, Asus P5Q Deluxe, 4 gigs Corsair Dominator 1066 RAM, 2x Asus 256MB fanless video cards, 3x W.D. 320 gig SATA drives, 2x 250 gig removable backup drives, I-Star 400-6Q case, Sony Lightscribe DVD, Noctua fans, I-Star 580 watt power supply, ADS Pyro Firewire, Scythe Ninja Heatsink, Kensington Expert Mouse, Logitech Trakball, 4x video monitors