Supporting Windows

The OS should be on a Mirror (0+1), it's a waste of disk to stripe it (Raid 5) and will slow performance.
Raid 5 is enough for the other stuff, but SQL logs and data should be on separate spindles due to the way data writes to the disks.

The boxes I usually configure are SMS\SCCm only writing to a Production SQL on a separate box\VM due to the configuration requirements for SQL to get max performance.

Doing a single server implementation means sacrificing performance in either SCCM\SMS or SQL (although it's less noticible in smaller environments).

That's a tiny bit backwards.

Raid 0 = Striped (High performance especially in database access time, low reliability, does not reduce available storage, do not use if you care at all about the data on this volume)
Raid 1 = Mirrored (No performance boost, high reliability, reduces total available storage by 50%)
Raid 0+1 or 1+0 = Both! Requires four disks minimum, but is both fast and reliable

Raid 5 = Striped with parity, this one is a little more complicated, but it basically is very good at sequential reads/writes (IE, large single files) and is still redundant and therefore reliable, and reduces available storage by the value of one disk. Raid 5 is typically best for file servers.

If the server you're talking about has 12 disks, and you want to put your SQL backend, SMS database, SQL transaction logs, and a distribution point on the same box, this is how I would configure it off the top of my head:

Operating system: Two disks @ Raid 1
SQL database: Four disks @ Raid 1+0
SQL transaction logs+ Distribution point: 6 disks @ Raid 5

The SQL transaction logs are kind of a throwaway, they could be placed on either the OS volume or the DP volume, as if you're running your entire SMS site from a single physical, I would imagine that you won't begin to run into scaling issues with log sizes. If your site is larger than I'm imagining it (5k+ clients) then I would recommend instead using a 4 disk Raid 5 for the distribution point, and having a dedicated 2 disk Raid 1 for the transaction logs. The key is to keep them off of the SQL database volume, you want your access time to be as fast and responsive as possible for a SQL database, as the number of writes/reads is much more important than the throughput for that application.