The MPF102 (Q1) can be replaced with a NTE451 or ECG451, but still widely available. JFET-N-CHAN, UHF/VHF AMP. The 2N3565 (Q1/Q2) can be replace with a 2N2222(A), BC107, BC108, BC109(A/B/C), NTE123A, or ECG123A. The TIP31 (Q3) can be replaced with a NTE196 or ECG196, but is a common type and widely available. The 'Touch Plate' can be anything non corrosive. I use a silver quarter. You can also use a small relay instead of the #53 bulb.