I believe most if not all of the current heavy rescues are walk around. I know 418 and 426 at one point had Ford chassis heavy rescues that were walk in bodies as was 414 before they got the red rescue they are running now.
Dave - Dr Feel Good is spot on, but just so YOU'RE clear (since I know you've lived out of the county for quite some time) all but 419 ARE walk-in but NOT ride-in. The crew is not able to ride in the back ala DCFD and FDNY. Hope that helps fellas.
Nate takes some great photos so they are well worth the wait........ The only ones I have are from Paul or nate not my own and not a rear shot to show the walk-in doors etc.