don't know about any existing apps but in general, you can spoof cli by:

1) using a specific field in a digital signalling scheme (like Euro-ISDN) to pass the desired presentation number. the network carrier must have configured the network trunk to permit this to supercede the actual line ID or it will just be ignored. normal use is for telesales/corporates etc. to present a non-geo to called parties which they can call back.

2) similar idea in SIP - I think that if you have an asterisk PBX or similar - i.e. full s/w control over SIP - then you can set any desired presentation number. in this case you are effectively a network 'operator' so you are less restricted

3) tromboned calls - where your outbound call is made to an intermediate telephony server and you provide it with the destination & desired CLI via DTMF. The intermediary then uses the above techniques to spoof the CLI for you.

as i say i have no idea about the services/app's being referred to here but I've been spoofing CLI for years using (1) and i've also provided (3) occasionally as a demo, or for legitimate purposes as part of my former job.