I think you might be a bit confused about virtualization. Which virtualization platform are you using? I havent come across one yet that doesnt allow you to map the drives however you choose. There are default configs and settings that allow the hypervisor to decide how to best make use of the available host's resources, but I have never seen an offering that doesnt allow you to override and say "Map virtual drive C:/ to physical drive C:/, D:/ to D:/", etc.
To answer your question, no, if you have 2 virtual drives, C:/ and D:/, but they both map to physical drive C:/, you wont gain any advantage by splitting up your database files across the virtual drives. If youre also bringing in networked drives, unless you have an incredible network config, youre actually probably going to lose performance since writes to external drives are expensive and time consuming. If you need that performance gain, I would recommend creating a new virtual drive and mapping it to a different, non-networked drive on the physical hardware.
You will probably also want to make sure that you dont put another high-load db on that virtual server with the same config, because if theyre both trying to access the physical drive at the same time, you will lose performance waiting for read/write time on that drive while the other DB is busy using it.
Overall, if you are worried about performance to the point of adding additional physical drives and splitting your mdf and tlog files across 2 physical pieces of hardware (which indicates youre probably already having resource constraints), i would probably advise against virtualizing if at all possible. Highly transactional, resource hungry DB's are not the best candidate for virtualization as you are inherently losing performance by splitting already scarce machine resources across multiple virtual clients and the hypervisor. The current setup I admin virtualizes everything except for the DB's for exactly this reason.