The main problem with OTP's is the fact that they can only be used once.
Would it be possible to use a random number that's, say, 512 digits, then use 256 of those for the (non-random) message, the 256 remaining ones to send half of the new pad (to be able to send a message back), then re-use those last 256 to send the second half?
As far as I can see, the clear text is obviously obscured (exactly the same as a standard OTP), and the re-used part is also secure because of the fact that the encrypted information is random as well.
The big difference from a two / many time pad is that the re-used part never comes into contact with any predictable data; it's an entirely different part of the message. So, as far as I can see, you could say the OTP encrypts the 256 digits, just as well as the 256 digits encrypt the OTP (both are completely random). Therefore, there should be no difference between the security of this and the regular way of using OTP's. If you were to re-use the part of the pad that encrypted the plain text, you would be vulnerable with regards to a known plain text attack.
Of course, it's not that efficient, because if the random number that encrypted the first message is discovered, all future numbers can be discovered. But other than that it could be pretty fun.