I like the concepts listed so far. It seems that something like the Sharpshooter or Trickster could be a full base class.
I think SteelDraco has a good point, that some concepts could be framed as variations of larger concepts. I had a related thought: When you wrote the original "Denarii" book, the idea of archetypes as presented in the Advanced Player's Guide had not yet been borne, but a lot of classes from that book could be repurposed that way. The beast master and bounty hunter seem like ranger archetypes, the corsair is a barbarian archetype, corbie and spy from rogue, martial artist from monk, knight from fighter, and so on. It's probably something I could retrofit on my own, but would that be something you might consider doing, either for the original Denarii classes or these new ones?
Archetypes are really just Alternate Class Features from Unearthed Arcana (3e). In fact, many of the classes in FoD are based around a similar concept, but in creating a new base class, I am free to do things like breaking up existing progressions or changing the skill list. The Corsair and its much maligned full BAB/full sneak attack combination is really just a Fighter with both sneak attack and the "Thug" option activated, then Pathfinderized by filling in the empty space with flavorful, piratical abilities. Similarly, the Beastmaster is a Barbarian with an animal companion isntead of rage, and then further tweaked until I was satisfied.
The corbie is something different. I started with a full BAB progression, then started hunting around for any rogue, bard, sorcerer, or other abilities I could find that suggested skill or luck. I love creating new things, but why reinvent the wheel? After carting off everything that wasn't bolted down, I expanded on the concept by creating new abilities and reshaped the class several times.
As far as archetypes for FoD goes... there's not much point for, say, the Spy. In fact, it would not surprise me if I found out that whoever wrote the Spy archetype in APG for the Rogue had read my work. The Spy is basically a Rogue archetype, plus a little love. I think the extra attention to making the different aspects work together makes it better than an archetype. But it would be possible, and possibly worthwhile, to make archetypes for the Beastmaster, Corbie, etc. The incentive is not strong, however.
For instance, what if I wanted to make a Beastmaster archetype that focused on a savage riding beast? I could tweak some of abilities so that they only got a single companion, change more general bonuses to riding abilities, and so forth. But the result is going to be only slightly different from the Beastmaster, and would be increasingly similar to an APG barbarian with the savage rider archetype. Which, by the way, bears more than a slight resemblance to the Wild Rider (variant barbarian class) from Unorthodox Barbarians.