If your kids were going to be 22 months apart...would you get a second crib or move the toddler to a toddler/twin bed?

Here are some of the things we're thinking about:

-We'd likely want to make the move before the baby comes, so, by 20 months or so. Baby will probably be in our room for a month or two, but I'd want to make a clean crib-break for DD before we bring the baby home.

-DH built DD's crib, so I'd love for it to be our only crib. Maybe silly, but true. Family heirlooms and all that.

-Worried about reasoning with my headstrong toddler when she's only 18-20 months old about staying in bed. She's an AWESOME nighttime sleeper and I'm terrified to mess that up.

-DD will stay in her same room--the crib would just move to the nursery if that what we decide.

What would you do? What DID you do in a similar situation?