Hmm - this is the first time of me hearing this, I was told because of the gun system that we would not sell it to anyone including our allies, NATO members included, but I may be wrong.
50 A-10A's were offered by US in 1994 and the sale was approved by the Congress. The aircraft were to be selected from AMARC reserves IIRC. The offer was surprisingly refused: Surprisingly, because mid 90's were the hottest times during the struggle against seperatist terrorist organization PKK in East and SouthEast Anatolia as well as Northern Iraq. Possible reasons for the refusal were:
1. Logistics plus cost to assimilate the aircraft into the squadron+operations+doctrine infrastructure
2. Army Aviation - Air Force disaggreement on which bracnh will operate the aircraft - similar to the one in USAF - US Army. AFAIK, US Army had planned to operate some A-10's.
3. Bad condition of the offered airframes.
4. Limited capability, especially inability to operate in night and adverse weather.
TuAF F-15 procurement, AFAIK, came to the agenda twice: First around 1998 when Greece announced plans to procure 40(?) F-15H's. The number was around 80 F-15E's.
The second case was during 2003, just before the OIF. During negotiations with the Turkish government for use of bases to conduct operations in Northern Iraq, USA offered Turkey a huge, repeat huge list of surplus and low-price weaponry of all scale: from LPD to HMMWV's. Among the list was at least two squadrons of F-15A/B's. There were rumors that Malatya MJB's infrastructure was modernized in order to accomodate the Eagle.
When the Turkish Parliament refused the bill for US troops' use of Turkish bases for jump point, the offer went to the garbage bin; so the plans to induct F-15A/B/C/D/E/XX.