Hello Rob,
Let's discuss the source first. The output power you are targeting is 264W (24V x 11A). Assuming 85% conversion efficiency as a starting point, you would need 310W of available input power. At 14V input, this translates to 22A of source current.
Assuming that the source can provide that kind of power, you will not be able to have a single switch solution. You would need some sort of parallel combinations with enough heatsinking. Whatever solution you pick, it will take quite a bit of board space to drive this much power.
You could try to parallel LM2588 boost converters (same as LM2587 but has frequency synchronization), here is a diagram (http://wwwd.national.com/national/PowerMB.nsf/(approved-attachments)/213EFF179DB67284882568CD006874CE/$File/Parallel+Regulators+to+Boost+Current.pdf). However, you would need more than 2 of them to get the output current. Using an external clock to drive the sync pin and offset the switching phases would be helpful. Also good board layout will be very critical in this case for proper operation.
Out of curiosity, what is your application that needs 24V and 11A? Is it some sort of a motor? Also, if you don't mind sharing, what are you using for your source?
Cheers,
Denislav