Here's my take: Let's look at another often used LLL acronym, VIP. Then look at VIPerson. It simply loses it's luster. In general, going partial-acronym happens a lot, usually to shorten the full name, and happens a lot with businesses utilizing a personal name (like HK Bentley or GAR Appraisals, 2 fresh in my head). However, people are already used to VIP and it's full meaning, Very Important Person. VIP has been widely keyworded such that it means high quality and elite...I don't know how that began, but it's fairly widely used that way now. So when you spell out part of it, or use only part of it with another word, it looks to people like taking part of a word and putting it with another part, and it's magnified by the fact that it's partial acronym partial spelled-out. With Top Level Domain being a technical term within the domain industry, I think you really have an uphill battle brandably keywording TLD (branding it to mean "domain" or TL to mean "high quality"). TLD honestly isn't a hugely popular term in its normal use anyways (not a lot of domain related websites have TLD in their names), so combine all that together and you've pretty much got reg fee names in tldomain.org, tldomainer.com, and tldrops.com.
I'm still not a fan of tldhunter.com because again you're trying to brand TLD to mean "domain", and I just think it you would have to advertise the hell out of it and have a cool site in order for that to work. tldscout.com is better, as you could mean it to scope out domain drops in a particular extension, effectively "scouting" the TLD, though that's kind of a roundabout way of saying a site has droplists or whatever.
Personally, I think if you're going to go for a brand name for a domain site, or for any site really, use the ol' thesaurus and Google and try to find replacement words for one of the words you want in the name. Sometimes you can simply think up synonyms of particular words and check and see if the name with the synonym is available. One of my better regged names, CompleteVideos.com, is a perfect example of a name I got because FullVideos.com was taken (and ironically I have seen that name since sell for $4k). I personally don't think the name loses that much...it's just a bit longer and has less searches from a generic perspective, but when you're doing brand names, you have a little more leway as people are after mostly generic names and not brand names.
A good exercise to do is look at 2 letter or 3 letter domains in a list (like one on Sedo), and try to think of acronyms for the letter combinations for the site you want. You'll find yourself coming up with some synonyms for certain words and/or changing words around or changing slightly what the name will get across in order to fit it to a letter combination. Before I ultimately settled on NameTrader.com for a domain related name where I could list my portfolio and ultimately in the future start a domain marketplace, I kicked around the idea of a LLL.com, and found the creative juices flowing based on what was available for sale.
Also note that at the time I purchased NameTrader.com, it was the most I ever spent on a domain, which brings up another point. I see many domainers have their own sites with lists of names for sale, and they can have some really great names...but the name of the site itself is BAD! I never understand how domainers, who are at the forefront of getting the message across to people that great domains help sites succeed, can fail to see the message when it comes to their own sites. It doesn't mean you have to spend your life savings on the name, but seek out premium names, and try to get the best deal. I could have been at DNX.com, DomainTrader.com, Domainex.com, DNT.com, etc., but NameTrader.com was the best deal I could get, and I've come to love it just as much as those others and much better than anything domain related I've ever hand-regged (the best being probably DomainAssociate.com, though I'm better at finding great expired domains than a lot of people).