Travel agents and deposits

Pondering a trip in October to Boston and Toronto. Are there any travel agents that let you book now and pay later? I know VH do, but any others?

I assume the e-ticket is not issued until paid in full though, so I wouldn't be able to reserve my seat immediately?

TIA! Mike.

[preiffer]

I thin Airline Network allow deposits on certain packages. Might be worth a try...

With VS/VH, you can allocate your seat straight away - I've done this for my VH booking that won't be "finalised" until October this year. I already have the VS reference and seat allocation though.