The most comfortable guitar I've ever played is a Stratocaster. I feel like the spacing between the frets is perfect, and playing the high notes is comfortable. I also have a 24 fret Ibanez, which in comparison has frets that feel cramped and difficult to comfortably play. These two guitars have the same scale length, 25.5 inches. If I wanted to get the same spacing between the frets as is on a Strat for a 24 fret guitar, what scale length should I look for? Should I get a baritone guitar? Am I asking the right questions in my search for a more comfortable 24 fret neck? Thanks in advance for advice.
You don't understand "scale."

On two guitars with a 25.5" scale neck, the frets will be exactly the same distance apart. Measure the distance from the nut to the 12th fret, and if both really have 25.5" scale necks, that distance will be exactly the same. As you move up the neck on any guitar, the frets get closer together (there's a formula for that). Those additional frets on the 24-fret guitar would be exactly the same size on the Strat if the strat's fretboard were extended (though you'd have to move the strat's neck pickup to give them the extra room).
There ARE guitars with longer scale fretboards, with 27" and 28" being the most common next step. While the upper frets on these guitars are very *slightly* roomier, the distances between ALL the frets will increase proportionally, with the greatest measured distance change occurring between the first few frets. If you have smallish hands, you may find THAT end of the fretboard becoming uncomfortable for chording.

A 27" scale guitar is NOT necessarily a Baritone guitar. "Baritone-ness" depends entirely on how you tune the guitar. You can (and a lot of folks do) tune a 27" scale guitar to E standard, and with the same gauges of strings that are commonly used on a 25.5" guitar. Jim Soloway used to famously build his "Swan" guitars with a 27" scale for jazz players who wanted a bit more comfort chording higher up and who wanted the clarity of the more "piano-like" lower end from the slightly longer strings.

Bear in mind that as you move up in scale, bending requires a greater distance of "push" across the neck to achieve the same pitch change. This is why I prefer a slightly wider neck on longer scale guitars (assuming that I'm going to be doing a lot of bending). Soloway's guitars offered a 1 13/16ths" width at the nut (most guitars are 1 11/16ths or 1 5/8ths" there). It's not unusual to find a 1 3/4" nut width on guitars with a Floyd Rose, but most guitars will narrow back down to a standard width at the bridge, and the advantage of the extra width is all but gone by the 12th fret. On Soloway's guitars, that extra 1/8th" was maintained ALL the way up the fretboard and the bridge itself was ALSO an extra 1/8th" wider. Very cool.
Quote by Juice Face
So would it be the fret size I need to look at?

The frets themselves can be wider or narrower at the base of the fret. But at the pinnacle or "crown" of each fret, they'll be the same distance apart. Guitars with Jumbo frets will often have frets that are wider at the base of the fret (and taller). At a guess, your Ibanez has these, while the Fender has skinnier frets (and they're likely lower as well).

Bear this in mind, though. Your technique should be light enough that the extra width shouldn't matter much. You never want to be pulling the string all the way down to touch the fretboard wood anyway. The string only needs to maintain contact with the fret top. You've no doubt seen scalloped fretboards, where the wood has actually been dug away between frets so that there's no way for the string (or your finger, really) to make contact with the fretboard. This is just an exaggeration of the same thinking behind making the frets taller (jumbos). It should be slightly easier to bend and use side-to-side vibrato with taller frets because your fingers can get to the side of the string without encountering the drag of the fretboard wood itself.