Paul - maybe I am misunderstanding something; so, let me review what I do know:
In my post above, I asked if you had any citations to support your statement. Please understand, as an attorney and as someone who works with tax matters, I always like to see authoritative sources before making any definitive conclusions. Thank you for the citations you provided. However, none of the cites are authoritative. By authoritative, I mean information that can be used to reasonably justify taking a certain position. I wouldn't expect anyone to cite case law, or even statutes, in a forum such as this. I realize I did not ask for authoritative cites; however, I would prefer to see official IRS documents for something like this. Cites to other forum posts or even articles carry no authority - but they do at least provide more information. In addition, anytime anyone starts talking tax law/implications, etc... there are lots of opinions (some accurate, some woefully inaccurate) I strongly recommend that anyone discussing a tax issue should refer to IRS documents or tax cases for justifying any position.
I also asked how this situation (meaning the situation Tom described in the original post) was different from the scenario I provided a link to: IRS Publication 523. The reason I asked is that I could see no difference between Tom's situation and the situation described in Pub 523. The situation described in Pub 523 specifically states the homeowner CAN exclude from income any capital gains from the sale of the home. However, maybe I misunderstood something, so it's always good to clarify. I did not see that question addressed in your subsequent posts.
The information you linked to describes how the law has changed to affect a situation different from Tom's situation.
As I understand Tom's situation - he bought the home, will then rent the home, then sell the home. Under this situation we look at the 5 years immediately before the sale. If Tom:
1) owns the property for at least 2 of those 5 years;
2) lives in the home as main home for at least 2 of those 5 years;
3) and there was no rental use of the home BEFORE Tom starting living in the home as main home (in the 5 year period)
He CAN exclude all capital gain (assuming other conditions met.)
HOWEVER, in the 5 year period before the sale of a home, if someone:
1) owns the property for at least 2 of the 5 years;
2) lives in the home as main home for at least 2 of the 5 years;
3) and there was rental use of the home BEFORE starting to use as main home (in the 5 year period)
He CANNOT exclude all capital gain (the portion of capital gain attributed to the rental period before being used as a main home must be included in income)
AGAIN See IRS Publication 523.
Please let me know if there is anything I misunderstood about this situation.