Hi,
i run 17 Entrys and one bridge at the moment.
I dont plan to change the IP adresses or the ports and most of them are already paid for nearly two years and i dont see a reason to switch them off after that time so if more fallback directory mirrors are needed then feel free to add them:

D379A1CB8285748FFF64AE94296CA89878F25B22
9288B75B5FF8861EFF32A6BE8825CC38A4F9F8C2
EE4AF632058F0734C1426B1AD689F47445CA2056
B57A87009FA838471FB2227DDE68165AB2A2FCC4 
465D17C6FC297E3857B5C6F152006A1E212944EA
7AAF5597B18D82CC90CA95FB7976A1CEA4A32E06
39F91959416763AFD34DBEEC05474411B964B2DC
4DC4E6187F1193F2717A5E3DF5ACEBD6B162D5CC
57C6DF5B93E54EB9C8DB90029D9E9A1111BD34D2
3B07C500AC17E7B5A1EE616613E104A094AB87F3
8F6197E5508338B3E3A6BFF59F9EC8F21E1375FB
79E683340B80676DCEB029E48FBD36BC66EBDA1E
A86EC24F5B8B964F67AC7C27CE92842025983274
A9DB853547A6459AB5190E62BF2F7B8F068FEB0A

Some of them are still pretty new but i am sure they will get older:)