Looking for, in order of priority:

4x Stromkirk Noble
2x Skullcrack
3x Boros Reckoner
3x Burning-Tree Emissary
4x Flinthoof Boar
3x Stomping Grounds
1x Rootbound Crag
1x Zealous Conscripts

and lower priority:

3x Boros Charm
Any shocklands (worth of $9 each, if currently valued above that)

I'd much prefer to trade within standard.

Also most things in my tradelist are for sale with PayPal, and in addition I'm selling:

3x Thragtusk (Mint)
2x Angel of Serenity (Mint)

Assuming you wouldn't do

4x Stromkirk Noble
1x Hallowed Fountain

for the Mox Opal. I'm obviously willing to overpay for it since its Standard to Modern.

Added to and rearranged list