http://www.viperactions.com/ - Stiller Actions - They make a "tactical" line that's a drop in for Rem 700s that looked promising. I decided against it after reading several negative reviews on forums. Apparently, they're not very rugged. On shooter said that he broke the bolt stop twice and when he sent it in the second time, Stiller told him to be 'more gentle'. I think gentle is unacceptable for a tactical rifle, but that's just my opinion.
http://www.surgeonrifles.com/ - Surgeon Rifles - They make great tactical actions, from what I've read. I see where Surgeon rifles/actions are winning tactical competitions and results always speak louder than advertisement to me. I figure if it's good enough for the professionals, it's more than enough for me. The current leader in the "2012 Precision Rifle Series" is using a Surgeon and performing outstanding with it.
The down-side is the price, but with 338LM that's to be expected. I think the surgeons are going for $1400 - $1800 dollars baseline for a 338. That's some serious coin.
I bought a 700P in 338 LM for $1500 a few years back. I haven't even shot it yet.
I want to build a real tack-driver, super-accurate, takes-the-balls-off-a-fly-at-400yrds type sniper rifle. I figure I can buy a fine-tuned action and match bull barrel for cheaper than it would be to fix up that factory 700. Plus, I get the enjoyment and experience of doing all the research myself. Instead of buying what Remington has put together, I'll have to talk to lots of people and hear their opinions and really weigh the pros and cons of different materials/manufacturers. That should be a fun process and I could benefit from learning a lot about my rifle in the process.
I can't speak for dmorgil, but that's why I'm doing it the hard way instead of just buying a factory model to upgrade.