There is only one which goes up to 125cm and can do both - Besafe Beyond, but you need to buy the base as well so it becomes astronomically expensive.
At what age roughly are you thinking you'll want to forward face? And is your little one big/small/average size for age? Also, do you think it's likely you'll have another child in the next couple of years?
There are a couple of spin seats - Cybex Sirona Gi i-size and Britax Dualfix Plus - which have a weight limit of 20kg rather than 18kg, but still have the 105cm limit.
Are you hoping for a seat which will incorporate the high back booster stage, or something which will let you forward face with a 5 point harness? It is possible to buy what they call "All Stages" seats, Silver Cross Motion All Size is the best rated one for example, but it is worth being aware that they do represent somewhat of a compromise, because the job that you want a forward or rear facing harnessed seat to do (stay in place, be sturdy, contain the child and support its own integral harness) is very different from the job you want a high back booster seat to do (be light and flexible, allow the seatbelt to route with minimal distortion, be very adjustable from ~4-12 years) and so it's impossible to optimise the seat for both jobs at once.
In ideal terms you want a seat which does one job e.g. an extended rear facing seat up to 125cm and then a separate high back booster for the forward facing stage. There are some scenarios where it's beneficial to cover two jobs (e.g. spin seats) in order to give you some flexibility in return, but the more jobs you ask a seat to cover, the more difficult it is to optimise the design for everything you're asking it to do.