Bitlocker encrypted drives should be possible using imaging since the LANDesk tool is sector based anyway. I haven't tried this, but the drive is encrypted so sector based is required, I have no idea whether it is possible to extend the drive normally with the imaging process though, that might be something you have to do in windows after it has booted up.
Bitlocker isn't the most fantastic product out there though. I much prefer other solutions including the LANDesk partnership with Credant.
Deploying multiple partitions. Doable with scripting, don't have any examples I can provide though so will need to hand that over to others.Provisioning does give you drive partitioning options too so you can take a look at what that provides.
LANDesk Silver ESP
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The best thing you can do is boot to WinPE and run the LANDesk imaging tool once manually (use 'net use' from a command prompt to get to your share that hosts ImageW.exe, the LANDesk imaging tool). You will be guided through the restore or creation of the image and at the end you can choose 'Show Command Line' to get your parameters exactly how you need them.
Partitioning can be done through Provisioning partitioning actions or by calling diskpart.exe with /s and an answer file. You can choose what way you feel most comfortable with.