Thanks to airblader for pointing me into the right direction :)
Here is the solution I came up with by utilizing pango markup:
i3statuswrapper.sh:
1 #!/bin/bash
2
3 function f_ram()
4 {
5 echo $(free | grep Mem | awk '{printf("%.0fMiB/%.0fMiB", $3/1024, $2/1024)}')
6 }
7
8 function f_uptime()
9 {
10 echo $(uptime -p)
11 }
12
13 echo '{ "version": 1 }'
14 echo '['
15 echo '[]'
16
17 i3status | while :
18 do
19 read line
20 ram_s=$(f_ram)
21 uptime_s=$(f_uptime)
22 full="UP: $uptime_s | RAM: $ram_s | $line"
23
24 echo ",[{\"name\": \"all\",\"full_text\":\"<span font='DejaVu Sans Mono'>"$full"</span>\",\"align\": \"right\",\"urgent\": false,\"separator\": false,\"markup\": \"pango\"}]"
25 done
i3status/config:
...
# ordinary config
14 order += "cpu_usage"
15 order += "disk /media"
16 order += "disk /home"
17 order += "disk /"
18 order += "volume master"
19 order += "tztime local"
...
i3/config:
144 bar {
145 status_command /home/USER/.config/i3status/i3statuswrapper.sh
146
147
148 font pango:RealChinese 10
...
159 }