You have already tried various types of logic analyzer, but you’re failed to find the one that suit you better? Then, why keep on the searching, as you can develop one for yourself?
Yep, you will have a brand new and simple low-cost logic analyzer, which is uses the PIC48F252(5) as the capture device and a windows based PC for the display purpose.
The LOGAN18 project it’s not a tough task to develop with, where you have to prepare the PIC18F2525, some LEDs, transistors, capacitors and wires. Therefore, it won’t cost you too much, as most of the components are cheap and easy to find.
Those things that you might need to pay attention with are the different of two variants. One of them is a simple version that uses a MAXIM level converter and it is works well with the 115 kBaud. Another one is an USB version, which it will support the transfer rates of 500 kbit (PIC with a 10 MHz crystal) or doubled up to 1000 kbit (PIC with a 12MHz crystal).
You can find the schematic diagram here.