What about putting up some flyers around the neighborhood with pictures of what was stolen? Or just leaving them on people's doorsteps... don't put your address, just your name & phone number.
"The following items were stolen from my home on (date) at approximately (time)... anyone having any information please contact (name & phone number).
For all you know, it could be some kid that just told his Mom that his friend lent him the guitar & amp... a parent isn't going to necessarily know the value of what's stolen. Regardless, the more noise you make about it, the tougher its going to be to the thieves to try and sell the stuff.
If they only took the guitar stuff, and didn't ransack the house, then I really think its musician's that stole it, or at least someone that wanted guitar gear. Professional thieves are looking for cash and jewelry. They would work quickly, dumping pretty much every drawer in the house. They are looking for small, high-value, hard to identify items ("they took my gold necklace" is not nearly as incriminating as "they took my PRS Custom Blue 24"... you don't come across those every day).
This to me sounds like someone knew the gear was there, made a plan, and then executed it taking only the gear. They most likely knew how they were going to enter and exit the house. It does not sound like a random act. Could be, but I'll wager whoever did it had looked the house over several times and came up with a plan to take the stuff. Normal break-ins are usually pretty messy on the inside.
Good luck!