HI Bun,
I have successfully used clomid to rectify a LP defect. Did you have a cd21 test done? If so was it within normal limits?
A luteal phase defect will not cause a loss as late as the ones you have suffered. A LP defect can cause problems in that implantation can occur up to 10 days after you ovulate (this is the late end of the scale but it can...) if your LP is only 11 days the dip in progesterone that occurs will interrupt the development of the pregnancy and you will have a chemical pregnancy. I have had 3 chemical pregnancies - all without clomid and all with an 11 day LP. If you implant earlier (each pregnancy will implant at a different time for each woman) say on 6 dpo then the pregnancy has time to implant and the the progesterone production isn't interrupted. So, this is why some women with shorter LP chave successful pregnancies.

The Clomid can be a very effective treatment for LP defect and personally it has been so for me. Clomid tricks your body into making more hormones (very basically) so all levels will be increased. This can cause hot flushes and mood swings (think she devil!!!) but I personally think it's a small price to pay for conceiving.
It is unusual to produce enough follies for a cycle to be cancelled on clomid. Usually you will begin on 5omgs - on this most women will produce 1 or 2 mature follies. I was on 150mgs of clomid the cycle I conceived my recent pregnancy on and I had 3 mature follies... My obs only cancels above 3 in a woman my age...(39)

Be aware though that on the first round of clomid your cycle may not be shorter. I am a late ovulator also and on my first round I ovulated on cd22. My subsequent cycles did shorten but never to 14days at ovulation. You will hear many stories similar to mine too. Conversley though you will hear many where women ovulate on cd14. It's just not a given...

I hope that has helped.

As for the NK theory. Yes it's controversial but it's certainly been a proven cause of many women suffering recurrent miscarriage. Dr S is a Sydney obsteric immunologist who deals with this. He will do phone interviews.
He does endometrial biopsies but they have to be done in his lab as he uses specialised testing that can only be done there.

If you have had 2 early losses it is HIGHLY likely that your next pregnancy will stick. However, I am a great believer in intuition. If you feel there is more to this - be like a pit bull and dont' let up. If you need any more information and I can help I would be more than happy. Good luck Bun