I've often thought about grabbing a bunch of folks with a similar relevant skill set, investing 6-12 months in training them, and then running a hugely profitable consulting company for a while. The problem being it's hard to prevent people from hanging out for your 12 months of training, and then jumping ship to do their own thing afterward...
I ran a successful consulting business many years ago (and hated it). One of the things you learn is that you live and die by the quality of the people you can deploy because that goes straight to your reputation. In practice, consulting businesses are very difficult to scale. While you may start out high-end with a great reputation because you really know what you are doing, it is very difficult to bring in additional people with your level of skill because there is almost no overhead to them working independently. As a result, "scale up" often involves diluting the quality of your overall team to the point where the rates you can charge decline as well. Consequently, you either have to run a very small boutique consulting shop that can maintain its standards and billing rate or run a large generic shop that makes up for the lower billing rate in volume. For people that care about the quality of their work, the former is more rewarding but the economics work out such that you will make about as much money by going direct as a highly-paid contractor to another company.
But I agree with your assessment of consulting firms and the scaling/quality issues therein. I also feel that consulting shops expenses tend to scale a lot closer to profits than some other businesses, so I stay out of it:)
Quite possibly OpenBSD (sys-admin/net-admin).
Kernel hacker specializing in odd OS (OpenBSD, FreeBSD, the new Solaris distro, etc).
Ruby on Rails used to demand high compensation back in 2006.
Clojure and maybe Scala might be on the same spot where Ruby/Rails was.
Sometimes what it takes is to be the top #5 consultants in a niche field (i.e.: PostgreSQL guru)
I'm employed by an eCommerce vendor myself, so I'm sure I'd have an intuitive understanding of general architecture, but actually understanding the internals of a system as an outsider seems like a difficult proposition.
The only real hope of learning it though is to have a company that you work for use ATG, send you to training, and get you coding on it every day.
This is why there is such a huge gap between the demand and supply of this skill set currently.
But of course, rumours are unconfirmed.
I'm unsure regarding Scala since a few articles have risen regarding getting burned by Scala (Yammer) or plainly suggested that Scala may not be it (David Pollack, one of the Scala celebrities).
Having said that, knowing Java developers, most (not all) of them would definitely flock to either Scala or Groovy instead of LISP. Have you heard anything about Groovy lately? Yep, nada, cricket. The cool kids (Yammer, Twitter) are using Scala (to some extend) so there you go.
Clojure on the other hand has that "LISP" tales behind it (LISP programmers are like gods or something like that) and it runs on Java so that gives people some kind of hope and smile on their face or something.
I don't know if either would be in high-demand but you may want to look around and do a bare minimum, out of the thin-air, lots of grain of salt type of assumption:
companies_who_use_X/people_who_sang_X_tunes = ratio_of_X_demand
or something like that.
e.g.: 10 people love scala, 10 companies using scala = 1
e.g.: 2 people love Clojure, 5 companies using clojure = 5/2 = 2.5
Guess who gets a better chance of aiming higher salary? :D
Of course that's just out of my arse type of calculation (for fun) :).
It's pretty easy actually: pay them well.
What happen if the developers are just that kind of people? i.e.: wanting to be their own man strutting their dongle around?
It's pretty easy to say than to do it :D
As far as your second example of people, I don't think enough people are like that to warrant consideration. People are more likely to stay with a company beyond the point of rationality.