Nimbostratus
CirrocumulusYou shouldn't have any issues... (Famous last words).
The shared config is the important part when configuring clusters. And shared config doesn't include interface (Or Trunk) names. They're only referred to by VLANs.
On all my bigip's I include the port-channel name in the trunk name. And because I use vPC's, they're all different between cluster members... No issues. I don't see that you'd have any difference just because one cluster member has the VLANs on a trunk rather than a physical interface. (Not sure I've tried this combination, because all mine started life out using vPC's)
However... if you are really nervous, you could always configure the trunk (vPC) with ONE interface. And simply put the second interface into the trunk (vPC) in production when you add the new blade...
H