OK, if you accept the ideas of the crossguard lightsaber and the lightsaber pike, combining the two into something like a spear with small transverse blades isn't really too far fetched. Unfortunately, it isn't quite possible with the rules we have since both of these options are standard hilts rather than attachments (like curved hilt and extended hilt). I could really see an argument for the crossguard hilt to be an attachment, but it's certainly not RAW.
That said, what other weird combos have you come up with?
I imagined a lightsaber pike with a curved hilt as looking something like a hockey stick with a straight shaft and a blade coming off at an angle. I guess it could have an s-curve to the shaft and a blade at a sharp angle to be something like a scythe.
What happens if you add curved hilt or extended hilt to a guard shoto? I'm not sure the resulting weapon would really be all that functional. Sure, in game stats it'll still work, but what the heck would it actually look like?
Crossguard lightsaber with extended hilt is going to look a lot like the classic bastard sword from D&D.
Crossguard lightsaber with curved hilt wouldn't bee too odd; there are a lot of curved swords with crossguards. I'd rather see something like a cortosis basket hilt for that curved thing, but alas...
Now curved and extended hilts together are going to be weird on many levels. I'm not really visualizing any good weapons that use both.