yes...there are adjusted gross income and "covered by another retirement plan" limitations for both traditional and roth ira's...however, most 401k plans also offer a "roth" option (maybe he's contributing to a roth through his 401k) and, as far as any excess or improper contributions are concerned? if you didn't include them with your tax return (non-deductible contributions still have a reporting requirement), i honestly don't think uncle sam is ever going to be able to figure that shit out...there's just WAY too much of that kind of information out there for them to ever be able to capture it all and make it right...generally speaking, if you don't tell them, they won't know...your broker (or whoever you make your ira contributions through) is supposed to know the rules and not let you make a contribution if you don't meet the requirements but, most of those people don't know shit about the tax laws...that said, i doubt that lestat has been making excess or improper contributions.
also, if you have another source of income (e.g., consulting) besides your regular job, you can set up and contribute to another retirement plan (besides the one at your employer) as long as you are generating net income from that other activity...it will still be subject to certain maximum contribution limitations but, there are plenty of legal ways to still be able to feather your nest with pre-tax or (sometimes) roth dollars without running afoul of the tax code