Funny, I'm working on the same problem with dtnetfx3_x64 and a 1603 error. I added /v"ALLUSERS=1" and it seems to be working, so you could try that.
The full command would be dotnetfx3.0.exe /q /norestart /v"ALLUSERS=1">nul
Sorry, spoke too soon. It worked on the machines I tested, but it's failed on every one since. I'll post again if I find a real solution.
The problem I had tracks back to the DX9 software rasterizer, RGB9RAST. It's an MSI contained within the .NET framework package. It defaults to installing for only the current user, which never works through BladeLogic, but there's no way to override it and change to all users (ALLUSERS=1).
The fix I found is kind of ugly, but it works--at least for x64. Once the rasterizer is installed, the .NET installer seems to go right through, but first you have to find the rasterizer. Follow the instructions in http://msdn2.microsoft.com/en-us/library/aa964979.aspx for extracting the components. Then locate RGB9RAST.msi and add it to the depot as an MSI package. You don't need to change the install command or add any custom properties, but I'd recommend changing the uninstall command since the MSI can't be uninstalled. Then create a BLPackage containing both the rasterizer MSI and .NET framework custom software, in that order.
I did find one weird quirk. The .NET installer fails if .NET is already installed. I'm not sure why that happens.
I will try you second one.
One question: so if you do RGB9RAST install and then again load .net install there was no issue as far as trying reinstall RGB9RAST?
Sorry, been away from this for a while. All the RGB9RAST installer does is lay down a file under Windows along with a registry entry or two. It doesn't register as an application or make any other changes I can recognize, so I'm not sure why they set it up to run user-specific.
As far as I can tell, the process only works because the RGB9RAST package detects the existing file and registry entry and skips the installation. If it tried to reinstall over the existing file it would probably fail the whole .NET installation.