The Enterprise dropped off the 3 runabouts originally assigned to DS9 in "Emissary", so it can carry at least that many, but we don't know where they were stored.
Those craft could even have been towed externally. Similarly, the single runabout seen in TNG "Timescape" need not have been carried internally by the E-D, or even been part of the complement of that starship; it may have been a completely separate courier vessel, to be sent to another destination eventually either under an E-D shuttle pilot or even under automatic control.
However, it shouldn't be difficult to fit one runabout aboard the E-D, and three should fit in as well. If the door size becomes a problem, there's always the overhead hatch on the main bay (at least according to the backstage material).
I'd brought the Shelley type ship up as a possible carrier in an earlier thread but there was very little agreement.
There are two possible "logical" sizes for those
Curry and
Raging Queen kitbashes from DS9: the one scaled according to the
Excelsior saucer, and the one scaled according to the
Constitution engines. Even the former leaves us with shuttlebay doors of at most
Excelsior size, though - and the DS9 fightercraft or runabouts wouldn't fit through those very well.
Even if they did get through, the deck beyond wouldn't be "through". The craft would have to descend at least one deck on some sort of elevator or shaft to reach the main body of the secondary hull. And this hull wouldn't seem to be very large inside, offering limited overhead clearance for most of the length.
So while those ships could carry a number of auxiliaries, they wouldn't be optimal fightercarriers. Not unless fighters of that bygone era were smaller than the DS9 ones...
Now the design seen in use by both the Maquis and Starfleet on DS9 can be called that, and it's not a whole lot bigger than modern-day large fighter-bomber aircraft, but it is still rather a lot bigger than the typical personnel shuttlecraft. Its warp drive is very unlikely to be a modification; it has large, well-defined warp nacelles built into its structure.
Agreed. The estimate of warp 5+ performance is a good one, because these things need to be a bit faster than runabouts or otherwise our heroes would have given chase in "The Maquis". Significantly higher performance is a bit unlikely, but possible - and if these can do warp 7 or 8 with the puny engines (no larger than runabout ones), they wouldn't need carriers for fleet action.
Timo Saloniemi