The TL072 is not very good noise wise and DC performance is also limited. There are considerable better modern OPs available (e.g. OPA140, OPA827, ADA4625 and similar). These also have pretty good DC performance. With the right JFETs one may get lower noise with discrete version, but the BF245 shown in the plan would already be higher noise.
To also get good DC performance with discrete JFET input, I would consider a 2nd JFET as current source or in a differential configuration and combining it with an OP. There are few different options, depending on wether DC performance or white noise is more important.
1 M impedance up to 100 kHz would need a very low input capacitance (less than some 1.5 pF !) - this would be main difficulty. Chances are one would need drain side bootstrapping or at least a cascode input stage.