I have MCB1700 board with LPC 1768. But I would like to know if there is board which have LPC 1788 on it from Keil?
For a complete novice, that makes sense.
But you say you've got a Keil MCB1700 board with LPC 1768. That should be enough to gain sufficient understanding of the tools to be able to move different hardware vendor - the tools remain the same; only hte hardware changes (and it's still the same family).
After all, when you get to applying the tools "for real", won't you be designing your own hardware (or getting it designed for you)...?