There's a way, provided that the ship you're using actually has a cockpit model (and that the viewpoint is positioned so that you can actually see anything from the cockpit, which is not always the case). Also, some ships have HUD screen on their cockpit which prevents visibility, and some have one that is partially transparent, and some have other glitches, but there
is a way...
You need to add
"show ship" flag to the ships with a modular table.
Example:
-Make a new directory path
..\FreeSpace2\COCKPITMOD\data\tables\-Create a new text file in the tables directory you just made and name it
visible_cockpits-shp.tbm [technical explanation - the *.tbm extension means it will be used as a modular table extension file, and the -shp part in the filename means it will extend the ships.tbl file]
-Copy this into the text file:
#Ship Classes
;;Terran Fighters. All the terran ships included here do have cockpits, but
;;some might or might not work well depending on how picky you are.
;;If you want to disable some ship model from showing, just remove or comment out
;;the appropriate section.
$Name: GTF Ulysses
+nocreate
$Flags: ( "show ship" )
+noreplace
$Name: GTF Hercules
+nocreate
$Flags: ( "show ship" )
+noreplace
$Name: GTF Loki
+nocreate
$Flags: ( "show ship" )
+noreplace
$Name: GTF Hercules Mark II
+nocreate
$Flags: ( "show ship" )
+noreplace
$Name: GTF Ares
+nocreate
$Flags: ( "show ship" )
+noreplace
$Name: GTF Erinyes
+nocreate
$Flags: ( "show ship" )
+noreplace
$Name: GTF Pegasus
+nocreate
$Flags: ( "show ship" )
+noreplace
$Name: GTF Perseus
+nocreate
$Flags: ( "show ship" )
+noreplace
;;Terran Bombers
$Name: GTB Medusa
+nocreate
$Flags: ( "show ship" )
+noreplace
$Name: GTB Ursa
+nocreate
$Flags: ( "show ship" )
+noreplace
$Name: GTB Zeus
+nocreate
$Flags: ( "show ship" )
+noreplace
;;Vasudan ships; note that none of the vasudan ships actually
;;has cockpits, but some of them work fairly well regardless, when you can see
;;the ship itself (Serapis being a good example of this)
$Name: GVF Seth
+nocreate
$Flags: ( "show ship" )
+noreplace
$Name: GVF Horus
+nocreate
$Flags: ( "show ship" )
+noreplace
$Name: GVF Thoth
+nocreate
$Flags: ( "show ship" )
+noreplace
$Name: GVF Serapis
+nocreate
$Flags: ( "show ship" )
+noreplace
$Name: GVF Tauret
+nocreate
$Flags: ( "show ship" )
+noreplace
$Name: GVB Sekhmet
+nocreate
$Flags: ( "show ship" )
+noreplace
$Name: GVB Osiris
+nocreate
$Flags: ( "show ship" )
+noreplace
#End
-go to Launcher's
Features tab and find "Custom flags" field. Add there an entry
-mod COCKPITMOD,mediavps. This will activate the visible cockpits mod and the mediaVP's.
Please remember that most of these cockpits were not designed to be used as anything else than externally viewed cockpits, so they are quite low-res and low-poly for this kind of use... additionally, several ships have issues with their HUD screen transparency (Hercs, Ursa, Perseus, actually most ships that have it) and cause strange glitches in rendering order due to this.
Also, in Vasudan ships you won't see cockpit but in some ships you can see the model's parts outside the cockpit (Osiris and Serapis work exceptionally well in forward view) but viewing around in the cockpit will make you see through the ship, which will probably look odd... but at least it'll allow you to keep a sense of view direction in relation to the ship. If you don't like some ship, just remove it from the table I posted, and only use those where it works well enough to not cause any glaring problems. Sadly, that list is short and you'll probably find yourself limited to the Ulysses (assuming that you have the cockpitted model of it; you'll eventually get this with the 3.6.10 mediaVP's), Loki, Zeus, Ares, maybe Medusa as well.
There is supposedly a better internal cockpit system to come, in which the cockpit model will be dealt with in a different way that should work way better than this way, which is to be hones bit of a hack... but as always, dates and deadlines are nonexistant until the release.
EDIT: I have just been informed that using $Flags on a modular table erases the existing flags on the ship from other tables, so it would cause some problems to appear...

Added a +noreplace entry to the table fields, but this only works on relatively recent builds.