Questions concerning OS selection
Hi,I've been going through this forum/google for the past few days trying to find answers to all of my questions. So far, I've gotten a lot of information, but nothing that clearly defines what I should do, so I thought I would toss out a question and see what all the gurus here had to say.

I'm looking at doing webhosting (including my own DC setup, but that's another issue entirely) for a niche group of people. The business is there, so I'm not asking for advice in terms of finances, business operation, and such. I just need technical suggestions.

I've been fairly impressed with the Sun machines as of late, and I'm considering a purchase of v40zs and v20zs. I was looking through the supported OS list for each server, and see the following:
Operating Systems supported by Sun Single Core Systems Dual Core Systems
Solaris 10 on x64 Yes Yes
Solaris 9 Operating System (x86 Platform Edition) 32-bit Yes Yes*
Red Hat Enterprise Linux 3.0 (32-bit/64-bit) Yes Pending
Red Hat Enterprise Linux 4.0 (32-bit) Pending Pending
SUSE Linux Enterprise Server 8.0 (64-bit) Yes No
SUSE Linux Enterprise Server 9.0 (64-bit) Yes Pending
Now, with all the reviews I've seen, Solaris 10 looks to be the best choice (if possible). Zones, and so forth, look really slick. I've installed 10 on a machine for testing, and was really impressed with DTrace and the like. However, installing/keeping software up to date on it looks to be atrocious right now. Unless my customers would be happy running two year old versions of software, I don't believe that I would be sticking to the sun provided applications. I could build everything from source, and track all the updates for everything manually, rebuilding the dependancies and such every time there is a security update, but that seems really, really tedious when we're talking about dozens of servers or more. No, blastwave/sunfreeware won't work, I don't really trust them as safe sources.
That being said, one thing I am needing is some kind of user management system/billing system/etc. I dug around in the forums for quite some time looking at all the options, H-Sphere looks to be the best for complete integration, but Cpanel looks like an alternative, with a collection of other tools added to it. Unfortunately, neither look to support any of the recent sun supported OSs for the servers. Uhg! Not only that, but I see H-Sphere has no 64 bit support, and the developers haven't replied about the issue either. Solaris support is absolutely not in their list of TODO, according to the devs. Cpanel on the other hand looks like is being developed for Solaris, but as the forums suggested, it's been in limbo for a long time. So, maybe it really won't ever be out for Solaris. Uhg again. RHEL 4 is not supported by sun (only 3) and tbh, I don't care much for RH nor their pricing scheme.
All of this being said, I hope you all understand what I'm looking for/asking, and I would greatly appreciate any input you could give. I'd love a single vendor solution, I was looking at the java enterprise system, but it looks like it's geared to corporate use, not geared to webhosting/etc, which is my primary need. I just need something that handles billing (of course there will be a person assigned to it, but I'd like to automate all that is safe to automate to eleminate user error), I'd like a support system for users, I'd like to have some kind of system in place to keep servers up to date in terms of security patches (much like freebsd's ports sytem, redhat's up2date, etc) and feature updates (aka having the ability to grab php5 and get it up and running without having to download every single source for it's dependancies, compiling and installing them all by hand). Finally, I'd like something that would automate/at least help with the management experience, aka cpanel/h-sphere's control panels which allow the admins to look at BW usage, charge based on overages (i think h-sphere does this automatically, cool!) and so forth. I'm sure the users would want a control panel too, so they could work with things.
So, I'm kind of stuck right now, I'm really not sure what to do, nor which direction to look, etc. Does anybody have any suggestions? Maybe there's a way to do all this in Solaris 10 (my ideal solution)?
Thank you for all of your help!
Cheers,
David