Hi, I just bought a used frame off of ebay. It was represented as a Merlin extra light.
I have contacted Merlin to identify the year of the bike, and they stated that because it was likely built before 2000 they can't be sure what year.
In addition, while changing the crankset I had a difficult time removing the DS bottom bracket cup. Had, in fact to take it to an LBS. It turns out I was dealing with an Italian bottom bracket shell, which Merlin claims was never standard. So I started thinking is this even a Merlin?
It appears to have a 1" steerer and straight seat stays, so it is probably a late 90s bike. The SN is stamped out in the outside dropout area and reads '0354'. This number is not included in the Merlin Museum SNs. Other peculiar features include an ovalized top tube ( appears to be sheet Ti that is rolled into a tube aka ABG style), and the atypical appearing cable stops. Also the front derailleur appears to be brazed on and all EL I have seen seem to have a clamp on style Front derailleur.
Can anyone help me identify this frame?

I've never heard of a Merlin having an Italian threaded bottom bracket, or an ovalized top tube. I'd be highly skeptical of the seller's claim that it is a Merlin.

I wonder if perhaps it was built by Litespeed, to another brand's specifications, and relabeled under that brand name? For example, both Merckx and Basso contracted Litespeed to build their ti frames, and both brands used Italian threaded bottom brackets on their steel bikes. (I don't know if the ti frames also incorporated the Italian threading.) However, that does not look like either a Merckx or a Basso ti, as I recall. Did Tommaso ever have ti frames in their line up?

Yes I agree. Tomasso did make some Ti frames, but none I looked at on google images had ovalized tts.
I think a distinguishing characteristic are the cable stops ( which appear conical ) and attach at the head tube not on the down tube like most period ABG bikes. Of the Ti makers only serrota attaches some of their cable stops at the head tube. Did serrotta ever make an ovalized top tube bicycle? And so they stamp the serial number on the drop out?