Since you want a desktop replacement and the desktop replacement is not up to the job then you should consider getting a desktop.

Investigate the small form factor PCs, e.g. Intel NUC.

I was able to get 4Tb of super fast storage into a NUC by making my own SSHD with bcache, a 256Gb SSD and a 4Tb laptop drive. It has a lower power i7 that is no Xeon and a mere 16Gb of RAM but it is plenty fast enough for me. It has plenty of NFS mounts, rsync scripts and version control things to always be up to date. Sometimes I take it home with me, other times it just sits on my desk.

I travel with a laptop or a Chromebook or nothing at all. I can work from anywhere. I believe client server apps need testing on different boxes, by using low end normal hardware I get the consumer experience, my 'above the fold' is their 'above the fold'.

I imagine that a gaming rig style NUC might be more what you are after rather than low power. With synergy keyboard/mouse sharing and plugging monitors into the NUC rather than the laptop I get freedom from having to cable up every time I get to my desk. Going home is quicker too.

I do have a bluetooth keyboard for phone/laptop/NUC so I can travel really light and can leave all computers at home and still work effectively. Obviously my laptop has a repository too.

So, if the NUC works for you then you might want to then look again at what laptop you use on a day to day basis. In my case the laptop has been relegated to a stay at home alternate dev environment. I don't bother lugging it around.

Instead I find myself carrying the Chromebook and my bluetooth keyboard/mouse. I use DNS for mapping my dev domains as ChromeOS cannot map the local network and see my NUC otherwise. I have all kinds of crouton things and remote desktop things but I just use the browser for everything on the Chromebook and may even get rid of the Ubuntu install. If I am on a train journey I can still take the laptop I relegated to home if I really need terminal windows.

I can and do take the NUC home at weekends if I want to do linux things with it to further improve its seamless integration or get it running lots of interesting virtual machines etc.

Think again about what machines your customers use if you are building web applications. With a remote dongle sized box doing your server side stuff you can go for a tasty ultrabook that works well with linux. Make sure that the wifi, mouse, touchscreen and the audio is going to work.

My laptop is some consumer Lenovo model, despite it being deaf to wifi and with no ethernet, it compares very nicely to the posh Thinkpads my colleagues use. The screen is nice and bright, it is touch screen and it even folds back - yoga - they call it. The keys are lit up chicklets and there is just the one trackpad. It now has 768Gb of SSDs. It does the job despite its consumer roots.

Meanwhile, the corporate specced Thinkpads my non-Apple colleagues use have slower SSDs or even spinning things, what appears to be two extra rows of keys, six more mouse buttons than are needed, some nipple in the middle of the keyboard and just a clumsy form factor with all kinds of dated port connectors.

Despite the millions of extra keys none of them are backlit and the screens can't be touched. People with these machines then plug in to a docking station and use an external keyboard/mouse. I have a feeling that these guys really should have gone for the consumer grade Lenovo rather than thinking they needed some extra executive features.

Developers can be the same to end up with cumbersome beasts that may have the specs you are after but are not nice to work with, e.g. over-Thinkpad-ised.