I'm looking for a way to get a secure storage compartment in my silhouette 1-2 vehicle.

Outside of the Hidden Storage talent, any suggestions?

Well, 'Cybernetic cavity' (rarity 3 but is restricted) gets you a rank of hidden storage for ~775 credits without you needing to have hidden storage in your talent tree, but I'm not sure if this would work for you.

I didn't want to alter my beautiful body

Isn't there a ship mod for storage compartments?

If you only need it to be secure and not hidden then would a secure box / bag / container that is strapped / welded / attached to the vehicle work?

Or just use a secure container that you carry rather than the vehicle?

Say to your GM that you want a secure storage compartment.

I won't presume to speak for your GM, but I'd be fine with letting you spend a HP to get a hidden compartment (as per the rules for that attachment) that would hold 1 or 2 Encumbrance, depending on the encumbrance capacity of the vehicle.